1. The Field of the Invention
The present invention relates to conductive articles, and more specifically articles having a conductive thin film coating with a predetermined electrical resistance and detectors for authenticating the predetermined electrical resistance.
2. Present State of the Art
As the technology in photocopiers, printers, and computers increases, the occurrence of sophisticated counterfeiting also increases. Counterfeiting runs a gambit much larger than just monetary notes. For example, counterfeiting can also be traced to credit cards, identification cards, coupons, tickets, legal documents, and other valuable papers. To combat counterfeiting, governments and other companies have developed unique approaches for distinguishing and authenticating original articles. Such approaches include manufacturing articles out of unique compositions and also incorporating water marks, colored threads, and intricate designs using novel ink compositions.
Although current approaches are useful in discouraging and discovering counterfeiting, such approaches are typically expensive to develop and apply. Furthermore, it is often apparent to the counterfeiter what unique aspect of an article needs to be duplicated in order to match an original article. For example, although colored threads are useful in authenticating original bills, counterfeiters are clearly aware of the presence of colored threads and thus can attempt to duplicate such threads.
A problem related to counterfeiting is that of tampering. For example, tampering with bottled drugs is a continuing concern to the public. Tampering also relates to the seal on envelopes and to other types of seals on important articles or papers. Although shrink wrap seals have relieved much of the public concern on many items, such seals can be easily replaced.